Abstract

In vitro embryo rescue culture of F1 progenies from crosses between different ploidy grapes

Crossing different ploidy grapes is an effective way to obtain new seedless cultivars. Although embryo rescue has been extensively applied in breeding seedless and triploid grapes, only a few improved cultivars have been developed. Based on preliminary studies, we set five crosses between tetraploid and diploid grape varieties to obtain new hybrid triploid germplasms. Additionally, we compared two different methods of performing in vitro embryo rescue and sowing in the development of hybrid triploid grape plants. The results showed that the germination rate of hybrid seeds was much lower (0-22.8%) than that of the self-pollinated seeds (50.9-61.2%) obtained though the same method of in vitro culture. Meanwhile, the seed germination rates of all crosses obtain through in vitro culture (0-61.2%) were higher than those obtained through sowing (0-42.0%). Identification of ploidy level confirmed that three lines obtained from the crosses of ‘Ruby Seedless (2x) x Black Olympia (4x)’ and ‘Big black (2x) x Kyoho (4x)’ were triploid, and one line from the cross of ‘Big black (2x) x Kyoho (4x)’ was haploid, and the others were diploid, tetraploid, or aneuploidy plants.Moreover, 4 haploid and 42 triploid surviving grape seedlings were planted in a vineyard after propagation. Therefore, an efficient system of breeding triploid seedless grapes using embryo rescue was established and 42 hybrid triploid germplasms were obtained for use in future studies.

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